Natural Selection Image Map

Darwin's Theory

In his famous book, Darwin stated that the idea of evolution was well understood by many others before his time. He reviewed the evidence that geologists and biologists had presented over many preceding decades.

What was new was Darwin's explanation that natural selection caused evolution. The basic idea was that the niches provided by Nature preferentially selected those emerging life forms that had inheritable traits that made them adapted to live in those niches.

 

Here, we show the value of camouflage, an adaptation that allows the fish to hide safely among the coral. See the fish to the lower right of the yellow fish? It is in the middle of the picture.

The essence of Natural Selection can be summarized as follows:

  • Individuals in a population are genetically varied
  • Reproduction produces many more offspring than are needed for a species to survive
  • The genetic traits that are passed on to new generations are those that are best adapted to the available niches.
  • As each generation reproduces, the incidence of the favorable traits gradually increases and comes to dominate the population. That population may become genetically isolated, thus forming a new species.

 

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